The present invention relates to the general field of open top containers and is particularly concerned with an assembly for selectively covering open top containers.
Vehicle cargo containers for transporting bulk material such as sawdust, gravel chip, cutter shavings and the like typically include open top boxes such as semi-trailers or the like defining side walls, a front wall, a rear wall and a floor. These open top containers are typically mechanically coupled to various types of vehicles such as cargo ships, railway carts and truck cabins for transporting goods between various locations.
During transportation in these so-called open top containers, there exists a substantial risk that a portion of the load may be blown out of the open-top of the container it may potentially cause not only unnecessary wastage of the transported goods but may also create a dangerous situation. For example, when the open-top container is attached to a truck cabin, some of the load accidentally blown out of the container may contaminate the road or highway as it whirls around thus causing difficult ground road conditions. It may also be blown directly towards the windshield of following vehicles creating a potentially disastrous situation.
Accordingly, in many areas, regulations have been implemented for the carriage of various loads, particularly on public highways requiring that open-top containers be provided with some type of covering structure for covering the loading aperture during transport. With the increasing number of accidents, these official requirements have become more and more astringent, sometimes requiring adequate coverage for the load on even short journeys.
Consequently, there has been an industry wide move to provide permanently installed flexible covers often referred to as tarpaulins or tarps that can be quickly rolled and unrolled by the driver so as to allow selective covering and uncovering of the load. When these permanently installed tarpaulins are used only occasionally they may be stored on the vehicle in a folded condition and unfolded over the body as and when required.
Various configurations of tarpaulins have been proposed. However, two configurations have proven to be particularly popular. One such configuration is the so called end-rolled tarpaulin which is gathered at one of the longitudinal ends of the container when not in use and moved along the body of the container between operative and stored positions. The end-rolled tarpaulins are typically gathered at the front end of the vehicle and are usually provided along their length with a number of transverse supporting bars which extend between the two longer side walls of the container. The end-rolled tarpaulins are typically moved by means of a pair of cables trained over pulleys and carrying the tarpaulins with them as they move.
The other type of permanently installed tarpaulin preferred by some hauliers is referred to as the side-rolled tarpaulin. These so called side-rolled tarpaulins which permanently extends the full length of the container body are rolled and unrolled about a roll rod that also extends the full length of the container body.
The use of prior art flexible closures such as prior art tarpaulins to close or cover the loading aperture of open top containers is associated with a number of drawbacks. One major shortcoming related to prior art assembles involves the difficulty often encountered in drawing the flexible closures into a proper extended or closed configuration. Indeed, the relatively heavy, bulky and flexible nature of large tarpaulins often cause such closures to be quite difficult to draw into properly extended or closed position for service as cover. The wind, rain and other environmental factors such as the presence of snow and ice often contribute to the difficulty that is encountered in moving tarpaulins into position. Therefore, due to the size of the box and of the tarpaulin such arrangements often requires the operator to stand in the container or to climb upon the load to perform the covering and uncovering operations. More specifically, the operator must often climb upon the load to connect and disconnect the separate parts involved and this is clearly undesirable since it is both time consuming and potentially dangerous.
Also, the rotatable rod on which the tarpaulin is rolled is typically rotated in one direction to roll the tarpaulin up and therefore open the open top of the cargo container. It is rotated in the opposite direction to unroll the tarpaulin and close the open top of the cargo container. Manual rotation is generally through a hand-crank. Such rotation, when performed with prior art assemblies, is often considered both tedious and unergonomical.
Another main drawback associated with prior art assemblies relates to the difficulty in keeping the tarpaulin taut during the rolling and unrolling operations which leads to, potential damage to the involved structures. This situation also leads to difficulties in establishing a suitable weather resistant seals about the perimeters of properly extended closures. The difficulty in keeping proper tension on the tarpaulin during rolling and unrolling operations is compounded in certain situations as for example when there exists a relatively moderate or high wind causing the tarpaulin to catch in the wind. In such instances, it is sometimes necessary to face the truck trailer in such a manner that the wind will not catch the tarpaulin. This may prove to be impossible when the wind changes direction. The difficulty in maintaining the tarpaulin in a taut state during rolling and unrolling operations leads to possible ripping or tearing of the tarpaulin and associated structures.
The difficulty in maintaining the tarpaulin in a taut state during rolling and unrolling operations also potentially leads to an improper seal which, in turn, may lead to potentially dangerous road condition and loss of material. This problem has been addressed by some of the prior art structures. However, most prior art structures or assemblies lack an effective means of maintaining the cover taut and in place during transportation especially at highway speeds. Indeed, the investment of time and effort that typically must be extended to properly secure a prior art tarpaulin to prevent its being drawn out of proper position by environmental conditions often proves to be unwieldy. Some prior art assemblies make use of a series of straps spaced along the tarpaulin which are secured to the container side wall by tying or clamping. These prior art assemblies have proven to be unsatisfactory since they have demonstrated a tendency to admit dust or rain under the tarpaulin and to allow the bulk material to flow between the peripheral edges of the tarpaulin and of the container. Also, at highway speeds, the tarpaulin is subject to billowing.
Another drawback associated with prior art structures relates to the difficulty in protectively storing the flexible tarpaulins after they have been retracted or withdrawn from their extended or closed position. This difficulty is directly related to the heavy, bulky and flexible nature of the large tarpaulins once they are in their rolled configuration.
A further problem associated with prior art structures for storing flexible tarpaulins is the lack of an arrangement which will prevent accidental movement of the tarpaulin., In other words, the lack of a locking structure or braking structure to hold the rolled or unrolled tarpaulin in a desired position is a problem which is not dealt with by many commercially available devices.
A still further problem associated with prior art tarpaulin closure systems is the need for the arrangement for maintaining adequate tautness in the tarpaulin and to ensure that the central tube remains parallel to the side walls. In this respect, it has been proposed in U.S. Pat. No. 5,002,328 to provide a system wherein the cable for winding or unwinding the tarpaulin uses a winch drum which is of a frustro-conical configuration.
Accordingly, there exists a need for an improved assembly or assembly for covering open top containers.
Advantages of the present invention include that the proposed assembly and method is specifically designed so as to facilitate drawing flexible closures such as conventional tarpaulins into proper extended or closed position by maintaining. Also, through the use of a specifically designed mechanism, the tarpaulin is maintained in a relatively taut condition throughout the movements thereof between the extended and closed position. Also, the proposed assembly facilitates and optimizes securing the flexible closures once they have been properly extended or closed. The established securement allows suitable weather resistant seals above the perimeters of the properly extended or closed closures.
Furthermore, the proposed assembly is specifically adapted to protectively store the flexible closures after they have been retracted or withdrawn from their extended or closed position. The manipulation of the tarpaulin is facilitated by specifically designed ergonomic characteristics which are inherently built into the proposed assembly. The proposed assembly includes a component adapted to facilitate ergonomical rolling and unrolling of the tarpaulin. The same component may also act as a brake when needed to selectively prevent unrolling of the tarpaulin. The proposed assembly is also designed so as to be economical to manufacture, durable in use and efficient in operation.
In accordance with an embodiment of the invention, there is provided an assembly for selectively rolling and unrolling a generally rectangular tarpaulin so as to correspondingly uncover and tautly cover a top opening of an open-topped container, the open-topped container having opposite first and second container end walls and opposite first and second container side walls, the tarpaulin being configured and sized so as to be able to fit in a covering relationship over the top opening, the tarpaulin defining corresponding first and second tarpaulin side edges and first and second tarpaulin end edges, the tarpaulin being secured adjacent the first tarpaulin side edge to the first container side wall, the assembly comprising: a rolling rod having a generally elongated configuration defining a rod longitudinal axis and a pair of opposed rod longitudinal ends, the rolling rod being secured to the tarpaulin adjacent the second tarpaulin edge, the rolling rod being operatively mounted over the top opening to roll up the tarpaulin therearound so as to uncover the top opening when rotated about the rod longitudinal axis towards the first container side wall in a first rod rotational direction, the rolling rod being also operatively mounted over the top opening to unroll the tarpaulin so as to cover the top opening when rotated about the rod longitudinal axis towards the second container side wall in a second rod rotational direction; a tarpaulin tensioning means attached to both the open-topped container and the rolling rod for tensioning the tarpaulin while the tarpaulin is both rolled and unrolled onto and from the rolling rod; the tarpaulin tensioning means including a winch drum attached to the rolling rod adjacent one of the rod longitudinal ends so as to rotate solidarly therewith; a tensioning cable defining a tensioning cable first end and a tensioning cable second end, the tensioning cable first end being attached to the winch drum allowing the tensioning cable to be wound around the winch drum when the rolling rod is rotated in the second rod rotational direction and allowing the tensioning cable to be unwound from the which drum when the rolling rod is rotational direction; a cable tensioning means attached to the tensioning cable is second end for resiliency maintaining the tensioning cable taut state.
In one embodiment, the which drum has a generally frustro-conical configuration tapering from a larger proximal end located proximally relative to the open-topped container to a smaller distal end located distally relative to the open-topped container.
Conveniently, the winch drum is provided with a generally helicoidally-shaped winding groove formed on its external surface, the winding groove being configured and sized for substantially fitting receiving the tensioning cable.
Preferably, the winch drum is further provided with a locking flange positioned adjacent the distal end, the locking flange being provided with a locking protuberance extending inwardly and at an angle towards the window groove.
Conveniently, the cable tensioning means includes a cable attachment component attached to the tensioning cable second end; the cable attachment component being slidably mounted within a tensioning housing attached to the open-topped container, the tensioning housing defining a housing peripheral wall and a housing proximal wall.
As aforementioned, the winch drum may have a generally frustro-conical configuration tapering from a larger proximal end located proximally relative to the open-topped container to a smaller distal end located distally relative to the open-topped container; wherein the winch drum being provided with a generally helicoidally-shaped winding groove formed on its external surface, the winding groove being configured and sized for substantially fittingly receiving the tensioning cable; the winch drum being provided with a locking flange positioned adjacent the distal end, the locking flange being provided with a locking protuberance extending inwardly and at an angle towards the winding groove; the cable tensioning means including a cable attachment component attached to the tensioning cable second end; the cable attachment component being slidably mounted within a tensioning housing attached to the open-topped container, the tensioning housing defining a housing peripheral wall and a housing proximal end wall; a biasing means is mounted between the cable attachment component and the housing proximal end wall for resiliency biasing the cable attachment component away from the housing proximal wall; the tensioning housing being configured, sized and positioned so that when the cable attachment component abuttingly contacts the housing proximal end wall the tensioning cable is frictionally squeezed between the locking protuberance and the winding groove providing a releasable locking action that releasably prevents the winch drum from rotating.
However, in a further embodiment of the present invention, rather than utilizing the winch drum having a generally frustro-conical configuration, one may utilize a conventional winch drum having a uniform diameter. In this embodiment, one can provide a tensioning structure which is designed to equalize the tension. To this end, there may be provided a winch drum of a conventional configuration (one with a consistent core diameter) in conjunction with a pulley assembly, the pulley assembly being movable and being spring mounted to provide for tension equalization.
Preferably, the assembly further comprises a clamping plate pivotally mounted on the first container end wall adjacent the top opening so as to extend transversally thereacross, the clamping plate being pivotable between a clamp first configuration wherein it squeezes the first tarpaulin end edge between the clamping plate and the upper peripheral edge of the first container end edge and a clamp second configuration wherein it lies in a spaced relationship relative to the upper peripheral edge of the first container end edge.
Conveniently, the assembly further comprises a pivoting means for pivoting the clamping plate between the clamp first and second configurations, the pivoting means including a clamp handle extending from the clamping plate to a position located externally adjacent the open-topped container below the top opening.
Preferably, the assembly further comprises a nesting means for nestingly receiving the tarpaulin when the latter is in a fully roll-up configuration, the nesting means including at least two generally xe2x80x9cLxe2x80x9d-shaped nesting arms pivotally mounted adjacent an upper peripheral edge of the first container side wall, the nesting arms being pivotally mounted to as to pivot between a retracted configuration wherein they lie in a generally parallel relationship relative to the first container side wall and a protracted configuration wherein they lie in a generally perpendicular relationship relative to the first container side wall.
Conveniently, the assembly further comprises at least one locking leg pivotally mounted adjacent an upper peripheral edge of the first container side wall, the locking leg being pivotally mounted to as to pivot between a storage configuration wherein it lies in a generally parallel relationship relative to the first container side wall and a locking configuration wherein it lie in a generally angled relationship relative to the first container side wall and abuttingly contacts the tarpaulin when the latter is in a fully roll-up configuration, the locking leg being attached to a locking leg biasing means for biasing the locking leg towards the storage configuration, the locking leg biasing means ensuring a frictional contact between the locking leg and the tarpaulin when the tarpaulin is in a fully roll-up configuration and nested in the nesting means.
Preferably, the assembly further comprises an actuating mechanism for selectively either simultaneously pivoting both the at least two nesting arms towards the protracted configuration and the locking leg towards the locking configuration or allowing both the at least two actuating arms and the locking leg to pivot respectively towards the retracted and storage configuration.
Preferably, the assembly further comprises an abutment means for abutting against the rolling rod when the tarpaulin covers the top opening and the rolling rod is positioned alongside the second container side wall.
Preferably, the rolling rod is mechanically coupled to a drive means for rotating the rolling rod about the rod longitudinal axis in both the first and second rod directions.
Conveniently, the drive means includes a planetary set of gear mechanically coupled to the rolling rod so as to transfer the rotational movement of the rolling rod to a driven shaft extending in a generally perpendicular relationship relative to the rolling rod, the driven shaft being mechanically coupled to a driving shaft by a driving shaft-to-driven shaft coupling means allowing the driving shaft to be oriented at an angle relative to the driven shaft.
Preferably, the assembly further comprises a releasable shaft locking means coupled to the driven shaft for selectively preventing the rotation of the driven shaft. Conveniently, the assembly further comprises a clamping plate pivotally mounted on the, first container end wall adjacent the top opening so as to extend transversally thereacross, the clamping plate being pivotable between a clamp first configuration wherein it squeezes the first tarpaulin end edge between the clamping plate and the upper peripheral edge of the first container end edge and a clamp second configuration wherein it lies in a spaced relationship relative to the upper peripheral edge of the first container end edge; a nesting means for nestingly receiving the tarpaulin when the latter is in a filly roll-up configuration, the nesting means including at least two generally xe2x80x9cLxe2x80x9d-shaped nesting arms pivotally mounted adjacent an upper peripheral edge of the first container side wall, the nesting arms being pivotally mounted to as to pivot between a retracted configuration wherein they lie in a generally parallel relationship relative to the first container side wall and a protracted configuration wherein they lie in a generally perpendicular relationship relative to the first container side wall.
Preferably, the assembly further comprises at least one supporting cable extending between the first and second container sides walls, the supporting cable being positioned so as to support the tarpaulin when the latter covers the top opening. Preferably, the supporting cable is attached between the first and second container side walls by a resilient supporting cable attachment means allowing the supporting cable to resiliency deform upon supporting the tarpaulin.